<template>
  <view class="con">
    <template v-if="viewWidth">
      <movable-area class="area" :style="{ height: areaHeight }" @mouseenter="mouseenter" @mouseleave="mouseleave">
        <movable-view v-for="(item, index) in imageList" :key="item.id" class="view" direction="all" :y="item.y"
          :x="item.x" :damping="40" :disabled="item.disable" @change="onChange($event, item)"
          @touchstart="touchstart(item)" @mousedown="touchstart(item)" @touchend="touchend(item)"
          @mouseup="touchend(item)" :style="{
          width: viewWidth + 'px', 
          height: viewWidth + 'px', 
          'z-index': item.zIndex, 
          opacity: item.opacity 
        }">
          <view class="area-con" :style="{
            width: childWidth, 
            height: childWidth, 
            borderRadius: borderRadius + 'rpx',
            transform: 'scale(' + item.scale + ')' 
          }">
            <image class="pre-image" :src="item.src" mode="aspectFill"></image>
            <view class="del-con" @click="delImages(item, index)" @touchstart.stop="delImageMp(item, index)"
              @touchend.stop="nothing()" @mousedown.stop="nothing()" @mouseup.stop="nothing()">
              <view class="del-wrap">
                <image class="del-image"
                  src="">
                </image>
              </view>
            </view>
          </view>
        </movable-view>
        <view class="add" v-if="imageList.length < number"
          :style="{ top: add.y, left: add.x, width: viewWidth + 'px', height: viewWidth + 'px' }" @click="addImages">
          <view class="add-wrap" :style="{ width: childWidth, height: childWidth, borderRadius: borderRadius + 'rpx' }">
            <image style="width: 54rpx;height: 54rpx;"
              src="">
            </image>
          </view>
        </view>
      </movable-area>

    </template>
  </view>
</template>

<script>
  export default {
    emits: ['input', 'update:modelValue'],
    props: {
      // 排序图片
      value: {
        type: Array,
        default: function() {
          return []
        }
      },
      // 排序图片
      modelValue: {
        type: Array,
        default: function() {
          return []
        }
      },
      // 从 list 元素对象中读取的键名
      keyName: {
        type: String,
        default: null
      },
      // 选择图片数量限制
      number: {
        type: Number,
        default: 6
      },
      // 图片父容器宽度（实际显示的图片宽度为 imageWidth / 1.1 ），单位 rpx
      // imageWidth > 0 则 cols 无效
      imageWidth: {
        type: Number,
        default: 0
      },
      // 图片列数
      cols: {
        type: Number,
        default: 3
      },
      // 图片圆角，单位 rpx
      borderRadius: {
        type: Number,
        default: 0
      },
      // 图片周围空白填充，单位 rpx
      padding: {
        type: Number,
        default: 10
      },
      // 拖动图片时放大倍数 [0, ∞)
      scale: {
        type: Number,
        default: 1.1
      },
      // 拖动图片时不透明度
      opacity: {
        type: Number,
        default: 0.7
      },
      // 自定义添加
      addImage: {
        type: Function,
        default: null
      },
      // 删除确认
      delImage: {
        type: Function,
        default: null
      }
    },
    data() {
      return {
        imageList: [],
        width: 0,
        add: {
          x: 0,
          y: 0
        },
        colsValue: 0,
        viewWidth: 0,
        tempItem: null,
        timer: null,
        changeStatus: true,
        preStatus: true,
        first: true,
      }
    },
    computed: {
      areaHeight() {
        let height = ''
        // return '355px'
        if (this.imageList.length < this.number) {
          height = (Math.ceil((this.imageList.length + 1) / this.colsValue) * this.viewWidth).toFixed() + 'px'
        } else {
          height = (Math.ceil(this.imageList.length / this.colsValue) * this.viewWidth).toFixed() + 'px'
        }
        // console.log('areaHeight', height)
        return height
      },
      childWidth() {
        return this.viewWidth - this.rpx2px(this.padding) * 2 + 'px'
      },
    },
    watch: {
      value: {
        handler(n) {
          if (!this.first && this.changeStatus) {
            // console.log('watch', n)
            let flag = false
            for (let i = 0; i < n.length; i++) {
              if (flag) {
                this.addProperties(this.getSrc(n[i]))
                continue
              }
              if (this.imageList.length === i || this.imageList[i].src !== this.getSrc(n[i])) {
                flag = true
                this.imageList.splice(i)
                this.addProperties(this.getSrc(n[i]))
              }
            }
          }
        },
        deep: true
      },
      modelValue: {
        handler(n) {
          if (!this.first && this.changeStatus) {
            // console.log('watch', n)
            let flag = false
            for (let i = 0; i < n.length; i++) {
              if (flag) {
                this.addProperties(this.getSrc(n[i]))
                continue
              }
              if (this.imageList.length === i || this.imageList[i].src !== this.getSrc(n[i])) {
                flag = true
                this.imageList.splice(i)
                this.addProperties(this.getSrc(n[i]))
              }
            }
          }
        },
        deep: true
      },
    },
    created() {
      this.width = uni.getSystemInfoSync().windowWidth
    },
    mounted() {
      const query = uni.createSelectorQuery().in(this)
      query.select('.con').boundingClientRect(data => {
        this.colsValue = this.cols
        this.viewWidth = data.width / this.cols
        if (this.imageWidth > 0) {
          this.viewWidth = this.rpx2px(this.imageWidth)
          this.colsValue = Math.floor(data.width / this.viewWidth)
        }
        let list = this.value
        // #ifdef VUE3
        list = this.modelValue
        // #endif
        for (let item of list) {
          this.addProperties(this.getSrc(item))
        }
        this.first = false

      })
      query.exec()
    },
    methods: {
      getSrc(item) {
        if(this.keyName !== null) {
          return item[this.keyName]
        }
        return item
      },
      onChange(e, item) {
        if (!item) return
        item.oldX = e.detail.x
        item.oldY = e.detail.y
        if (e.detail.source === 'touch') {
          if (item.moveEnd) {
            item.offset = Math.sqrt(Math.pow(item.oldX - item.absX * this.viewWidth, 2) + Math.pow(item.oldY - item
              .absY * this.viewWidth, 2))
          }
          let x = Math.floor((e.detail.x + this.viewWidth / 2) / this.viewWidth)
          if (x >= this.colsValue) return
          let y = Math.floor((e.detail.y + this.viewWidth / 2) / this.viewWidth)
          let index = this.colsValue * y + x
          if (item.index != index && index < this.imageList.length) {
            this.changeStatus = false
            for (let obj of this.imageList) {
              if (item.index > index && obj.index >= index && obj.index < item.index) {
                this.change(obj, 1)
              } else if (item.index < index && obj.index <= index && obj.index > item.index) {
                this.change(obj, -1)
              } else if (obj.id != item.id) {
                obj.offset = 0
                obj.x = obj.oldX
                obj.y = obj.oldY
                setTimeout(() => {
                  this.$nextTick(() => {
                    obj.x = obj.absX * this.viewWidth
                    obj.y = obj.absY * this.viewWidth
                  })
                }, 0)
              }
            }
            item.index = index
            item.absX = x
            item.absY = y
            if (!item.moveEnd) {
              setTimeout(() => {
                this.$nextTick(() => {
                  item.x = item.absX * this.viewWidth
                  item.y = item.absY * this.viewWidth
                })
              }, 0)
            }
            // console.log('bbb', JSON.parse(JSON.stringify(item)));
            this.sortList()
          }
        }
      },
      change(obj, i) {
        obj.index += i
        obj.offset = 0
        obj.x = obj.oldX
        obj.y = obj.oldY
        obj.absX = obj.index % this.colsValue
        obj.absY = Math.floor(obj.index / this.colsValue)
        setTimeout(() => {
          this.$nextTick(() => {
            obj.x = obj.absX * this.viewWidth
            obj.y = obj.absY * this.viewWidth
          })
        }, 0)
      },
      touchstart(item) {
        this.imageList.forEach(v => {
          v.zIndex = v.index + 9
        })
        item.zIndex = 99
        item.moveEnd = true
        this.tempItem = item
        this.timer = setTimeout(() => {
          item.scale = this.scale
          item.opacity = this.opacity
          clearTimeout(this.timer)
          this.timer = null
        }, 200)
      },
      touchend(item) {
        this.previewImage(item)
        item.scale = 1
        item.opacity = 1
        item.x = item.oldX
        item.y = item.oldY
        item.offset = 0
        item.moveEnd = false
        setTimeout(() => {
          this.$nextTick(() => {
            item.x = item.absX * this.viewWidth
            item.y = item.absY * this.viewWidth
            this.tempItem = null
            this.changeStatus = true
          })
          // console.log('ccc', JSON.parse(JSON.stringify(item)));
        }, 0)
        // console.log('ddd', JSON.parse(JSON.stringify(item)));
      },
      previewImage(item) {
        if (this.timer && this.preStatus && this.changeStatus && item.offset < 28.28) {
          clearTimeout(this.timer)
          this.timer = null
          const list = this.value || this.modelValue
          let srcList = list.map(v => this.getSrc(v))
          // console.log(list, srcList);
          uni.previewImage({
            urls: srcList,
            current: item.src,
            success: () => {
              this.preStatus = false
              setTimeout(() => {
                this.preStatus = true
              }, 600)
            },
            fail: (e) => {
              // console.log(e);
            }
          })
        } else if (this.timer) {
          clearTimeout(this.timer)
          this.timer = null
        }
      },
      mouseenter() {
        //#ifdef H5
        this.imageList.forEach(v => {
          v.disable = false
        })
        //#endif

      },
      mouseleave() {
        //#ifdef H5
        if (this.tempItem) {
          this.imageList.forEach(v => {
            v.disable = true
            v.zIndex = v.index + 9
            v.offset = 0
            v.moveEnd = false
            if (v.id == this.tempItem.id) {
              if (this.timer) {
                clearTimeout(this.timer)
                this.timer = null
              }
              v.scale = 1
              v.opacity = 1
              v.x = v.oldX
              v.y = v.oldY
              this.$nextTick(() => {
                v.x = v.absX * this.viewWidth
                v.y = v.absY * this.viewWidth
                this.tempItem = null
              })
            }
          })
          this.changeStatus = true
        }
        //#endif
      },
      addImages() {
        if (typeof this.addImage === 'function') {
          this.addImage.bind(this.$parent)()
        } else {
          let checkNumber = this.number - this.imageList.length
          uni.chooseImage({
            count: checkNumber,
            sourceType: ['album', 'camera'],
            success: res => {
              let count = checkNumber <= res.tempFilePaths.length ? checkNumber : res.tempFilePaths.length
              for (let i = 0; i < count; i++) {
                this.addProperties(res.tempFilePaths[i])
              }
              this.sortList()
            }
          })
        }
      },
      delImages(item, index) {
        if (typeof this.delImage === 'function') {
          this.delImage.bind(this.$parent)(() => {
            this.delImageHandle(item, index)
          })
        } else {
          this.delImageHandle(item, index)
        }
      },
      delImageHandle(item, index) {
        this.imageList.splice(index, 1)
        for (let obj of this.imageList) {
          if (obj.index > item.index) {
            obj.index -= 1
            obj.x = obj.oldX
            obj.y = obj.oldY
            obj.absX = obj.index % this.colsValue
            obj.absY = Math.floor(obj.index / this.colsValue)
            this.$nextTick(() => {
              obj.x = obj.absX * this.viewWidth
              obj.y = obj.absY * this.viewWidth
            })
          }
        }
        this.add.x = (this.imageList.length % this.colsValue) * this.viewWidth + 'px'
        this.add.y = Math.floor(this.imageList.length / this.colsValue) * this.viewWidth + 'px'
        this.sortList()
      },
      delImageMp(item, index) {
        //#ifdef MP
        this.delImages(item, index)
        //#endif
      },
      sortList() {
        // console.log('sortList');
        const result = []
        let source = this.value
        // #ifdef VUE3
        source = this.modelValue
        // #endif
        
        let list = this.imageList.slice()
        list.sort((a, b) => {
          return a.index - b.index
        })
        for (let s of list) {
          let item = source.find(d => this.getSrc(d) == s.src)
          if (item) {
            result.push(item)
          } else {
            if(this.keyName !== null) {
              result.push({
                [this.keyName]: s.src
              })
            } else {
              result.push(s.src)
            }
          }
        }
        
        this.$emit("input", result);
        this.$emit("update:modelValue", result);
      },
      addProperties(item) {
        // console.log(item);
        let absX = this.imageList.length % this.colsValue
        let absY = Math.floor(this.imageList.length / this.colsValue)
        let x = absX * this.viewWidth
        let y = absY * this.viewWidth
        this.imageList.push({
          src: item,
          x,
          y,
          oldX: x,
          oldY: y,
          absX,
          absY,
          scale: 1,
          zIndex: 9,
          opacity: 1,
          index: this.imageList.length,
          id: this.guid(16),
          disable: false,
          offset: 0,
          moveEnd: false
        })
        this.add.x = (this.imageList.length % this.colsValue) * this.viewWidth + 'px'
        this.add.y = Math.floor(this.imageList.length / this.colsValue) * this.viewWidth + 'px'
      },
      nothing() {},
      rpx2px(v) {
        return this.width * v / 750
      },
      guid(len = 32) {
        const chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('')
        const uuid = []
        const radix = chars.length
        for (let i = 0; i < len; i++) uuid[i] = chars[0 | Math.random() * radix]
        uuid.shift()
        return `u${uuid.join('')}`
      }
    }
  }
</script>

<style lang="scss" scoped>
  .con {
    // padding: 30rpx;

    .area {
      width: 100%;

      .view {
        display: flex;
        justify-content: center;
        align-items: center;

        .area-con {
          position: relative;
          overflow: hidden;

          .pre-image {
            width: 100%;
            height: 100%;
          }

          .del-con {
            position: absolute;
            top: 0rpx;
            right: 0rpx;
            padding: 0 0 20rpx 20rpx;

            .del-wrap {
              width: 36rpx;
              height: 36rpx;
              background-color: rgba(0, 0, 0, 0.4);
              border-radius: 0 0 0 10rpx;
              display: flex;
              justify-content: center;
              align-items: center;

              .del-image {
                width: 20rpx;
                height: 20rpx;
              }
            }
          }
        }
      }

      .add {
        position: absolute;
        display: flex;
        justify-content: center;
        align-items: center;

        .add-wrap {
          display: flex;
          justify-content: center;
          align-items: center;
          background-color: #eeeeee;
        }
      }
    }
  }
</style>
